The screed forms an intermediate layer on which the floor covering is laid or is leveled beforehand with a self-levelling compound. The most commonly used cement screed is the universal classic. It is waterproof and suitable for both indoor and outdoor use. Due to its strength, it is suitable for living spaces, basements, utility rooms and garages.

Cement screeds are divided into floating screeds, which are separated from the substrate by a sound or thermal insulation layer, and bonded screeds, which are glued directly to the substrate. And separate screeds, which are separated from the subfloor by a separating film. In residential areas, floating screeds are laid for good thermal and sound insulation. A heated screed or flowing screed can also be used for underfloor heating. 

In general, cement screed hardens more slowly than calcium sulphate screed, up to a month, and is also less flexible. It must be kept moist during the curing process to prevent cracking. Moisture can be maintained, for example, by laying a moistened geotextile or by covering the surface with PE foil. Pouring the screed is only recommended in warmer periods. It should also be noted that the standard thickness of the screed should be at least 30 mm. 

We recommend creating expansion joints for areas over 40 m². The purpose of expansion joints in a larger area is to allow the subfloors of the screed to move freely in relation to each other, thus preventing the transmission of vibrations and sound. If this is not necessary, a screed can also be laid in large areas without expansion joints due to the low expansion coefficient.

Anhydrite screeds offer many advantages over traditional cement screeds. They are easy to apply and dry quickly, saving time and making the job easier. These screeds are a liquid material that is spread on the surface. It can be machine-distributed to several connected rooms at once, meaning that it does not have to be handled with a bucket. In this case, the time-consuming spreading, compacting and smoothing are also not necessary. In practice, this means that the screed can be used to create larger areas without expansion joints and without additional reinforcement. Typically, this is a calcium sulphate based screed which is self-levelling and sets without tension, making it ideal for underfloor heating. Its great advantage is that it does not expand excessively in volume or shrink. 

Anhydrite self-levelling screeds are a more modern version of cement screeds. They differ mainly in the additives that affect their viscosity and thus their flowability. They are also much more flexible than cement screeds and have a smaller application thickness, which is advantageous in building renovation. Anhydrite screeds are self-levelling, which means creating an exact horizontal level (plane).

Anhydrite screeds have better thermal conductivity because the material wraps tightly around the underfloor heating pipes. This offers the best possible heat transfer between the underfloor heating pipes and the floor. For the subsequent installation of underfloor heating, the existing screed can be milled to allow the heating coils to be laid. However, the cellar ceiling must be insulated underneath. This type of screed must be kept moist during the curing process. As excess water evaporates from the wet-applied screed as it cures, it shrinks as it cures and causes the screed layer to separate from the substrate at the corners.

Whether to choose a floating or bonded screed depends on the specific needs of the project, as well as the type of flooring and the environment in which it will be installed. Floating screed is more suitable for domestic interiors and is slightly easier to apply. While bonded screed is more commonly used in commercial spaces and where high stability and durability of the floor is required.

Screed bonded to the subfloor is not a self-supporting structure as it copies all the deformations of the subfloor. It is mainly used as a levelling layer or to improve the properties of the floor surface. It is particularly durable and is therefore often used in garages or other areas subject to heavy loads.

The floating screed is then applied without direct attachment to the subfloor. It is usually separated from the subfloor by a separation layer (thermal or acoustic insulation). It is most commonly used in residential and civil engineering buildings. This screed acts completely independently of the subfloor, both horizontally and vertically. Thanks to its properties, it can effectively reduce the transmission of noise between floors and increase the comfort of the occupants.

Minimum floating floor thicknesses:

• F4 calcium sulphate floor screed: minimum 35 mm
• Calcium sulphate flowable screed from F5: 30 mm
• Calcium sulphate screed F4: 45 mm
• Calcium sulphate screed F5: 40 mm
• Calcium sulphate screed F7: 35 mm
• Cast asphalt screed IC10: 25 mm
• Cement screed F4: 45 mm
• Cementitious screed F5: 40 mm
• Maximum thicknesses of floating screeds
• Bonded screed: 50 mm
• Cast asphalt screeds: 40 mm

Modern, minimalist surfaces with an industrial look are achieved by using a screed that has the appearance of a visible screed as the final layer. It is a high quality screed, sanded and polished, with very good durability and long life.

It is also suitable for laying as a visible screed, but must be somewhat thicker. The hardness of the surface and the grain size must be chosen accurately so that the floor can withstand the load. In addition to the different types of composition, colouring agents can also be used to create a visually attractive appearance. This, however, requires a great deal of experience. For this type of screed, high absorption requires pore filling, and a seal coat based on epoxy resin or PUR to achieve stain protection of the surface. Waxing the surface is not sufficient here.

It is enriched with bitumen (asphalt), so it is fast-drying, waterproof and insensitive to temperature. It also has good thermal and acoustic insulation properties. It is highly load-bearing. Its elasticity compensates well for static stresses. Cast asphalt screed must be processed at high temperatures. The disadvantage is that it cannot be pumped, which makes it difficult to use on higher floors.

It usually contains epoxy resins or polyurethanes, making it completely insensitive to moisture and very resistant to water. Therefore, synthetic resin-based screeds are also suitable for special applications such as balcony slope levelling or various outdoor repairs. The great advantage of the synthetic resin screed is that it dries very quickly.

A specialty is magnesite screed, which is electrically conductive thanks to a mixture of magnesium oxide (MgO) and a solution of magnesium chloride and other organic and mineral fillers. This screed is suitable for areas where antistatic properties are required. Magnesite screed also has an extremely low dust content. The disadvantages are its sensitivity to moisture and the fact that it reacts with metals.

Thanks to its good thermal conductivity and thermal storage properties, it is very suitable for underfloor heating. The installation of underfloor heating looks like the heating pipes are laid in a serpentine pattern over the insulation and are then filled with a screed compound. The flowing screed is spread between the heating pipes to form a layer above them with a minimum pipe coverage of 3-4.5 cm, depending on the flexural strength class.

The cementitious screed should be able to store and conduct heat well. The material must also be heat resistant. The heating screed should be at least 4 cm high.

An anhydrite screed is a screed whose binder is calcium sulphate. It can also be used in dry construction. Anhydrite screed is usually 4-5 cm thick. However, it is absorbent and not resistant to moisture, so it can only be used in dry rooms. It is not recommended for use in wet areas such as bathrooms or kitchens or outdoors. It is also not always suitable for uninsulated floorboards as temperature differences can cause condensation on the masonry. Anhydrite screed is highly flexible and has strong tensile and flexural strength. It is non-flammable.